Detection and alarm system

ABSTRACT

A system for continuous monitoring of a physiological condition of a recipient arranged to alarm the recipient and a remote service center in case an abnormality in the physiological condition occurs. For that purpose the system comprises monitoring means provided with a set of electrodes to be arranged on the body of the recipient and to derive a signal related to said condition, detection means actuated by said electrodes and arranged to process said signal in order to derive a feature in the signal characteristic to said abnormality; alarm means arranged to trigger an alarm signal upon a detection of said feature by the detection means; transmission means arranged to transmit the alarm signal to a station responsive to said alarm signal. The system architecture is arranged in such a way that only the alarm signal is transferred to the station thus allowing the monitoring in a continuous way.

The invention relates to a system for detecting an abnormality in aphysiological condition of a user and for alerting people to saidabnormality, said system comprising monitor means for monitoring asignal representative of the physiological condition, said monitor meanscomprising sensor means arranged to be located on the body of the userfor detecting said signal; detection means actuated by said sensor meansand arranged to process said signal in order to derive a feature in thesignal characteristic to said abnormality; alarm means arranged totrigger an alarm signal upon a detection of said feature by thedetection means; transmission means arranged to transmit the alarmsignal to a station responsive to said alarm signal.

A system of a kind described in the opening paragraph is known from U.S.Pat. No. 5,228,449. The known system is arranged to monitor thephysiological condition of the user and for alerting people in case aproblem in said condition occurs. The known system comprises monitoringmeans provided with a set of electrodes. The monitoring means arearranged on the body of the user, a so-called user-side of the system inorder to pick up a signal related to the physiological condition, forexample ECG-signals. The known system further comprises transmittingmeans also arranged on the user-side of the system to transmit thepicked-up signal to a base unit located outside the user-side of thesystem. The base-unit performs an analysis of the transmitted signal inorder to derive a feature characteristic to a problem. For example, forcardiac applications a certain cardiac rate is a feature characteristicto a condition of a cardiac arrest. In case the analysis indicates thatthere is a problem in the physiological condition of the user an alarmis generated, which can be sound locally, for example at the user'shome, or at a remote location.

The known system has a disadvantage that for continuous monitoring of aphysiological condition a continuous data transmission has to take placeresulting in a high power consumption of the system leading to anecessity to frequently replace the local power supply of the system.

It is an object of the invention to provide a system as described in theopening paragraph, where the power consumption of the system is reducedleading to an improved durability of the system.

The system according to the invention is characterized in that thedetection means are arranged on a user-side of the system, the alarmsignal being the sole signal transmitted by the monitor means to saidstation. According to the technical measure of the invention a systemarchitecture is designed to achieve an ultra-low power consumptionleading to a feasibility of a true continuous monitoring of aphysiological condition. An example of said condition is a cardiacactivity, body temperature, respiration rate, encephalogram, etc. Thesystem according to the invention is arranged to perform a 24-hourmonitoring, where the signal analysis is performed on a body-worn unitwithout a need for a permanent wires-less connection to a unitperforming a data analysis. The data analysis is performed by means of aper se known software. The software can include a pre-set table wherecharacteristic features are identified. Therefore, according to thetechnical measure of the invention the power-consuming transmission to astation outside the user-side of the system occurs only in a situationwhere an abnormality in the physiological condition of the user isdetected. It is also possible that the features are ranked up accordingto the severity of the abnormality of the physiological condition beingmonitored. For example, for cardiac applications, a minor change in thecardiac cycle can be recognized as an alarm of the lowest category,where an occurrence of arrythmia or fibrillation can be ranked higher.The alarm signal can be ranked accordingly to the rank of the feature.

An embodiment of the system according to the invention is characterizedin that the station is a stationary home-based station arranged toforward the alarm signal automatically to a remote service center. Insituations when the user is suffering from a problem in thephysiological condition being monitored, the home-base station receivesan alarm signal to warn the user and/or a member of a family or aneighbor (to ask for assistance. In situations where the problem is theproblem of a high severity, for example a cardiac arrest a prompt andadequate medical response is necessary. According to an embodiment ofthe invention, the home-based station is arranged to forward the alarmsignal to the remote service center. An example of the remote servicecenter is a call center arranged to manage medical emergencies of akind. The remote service center will take over the management of theemergency and can inform the respective communal or medical sites aboutthe emergency, the address of the user, patient data and the probablediagnose. This enables the fast and adequate handling oflife-threatening abnormalities and adds to an improved survival chanceduring emergencies.

A further embodiment of the system according to the invention ischaracterized in that said home-based station is further arranged tocontrol a domestic device. An example of a domestic device is anelectronically adjustable door lock, or a tap water control or a controlof other domestic appliances, like irons, ovens, etc. According to thistechnical feature the user is ensured that the medical personnel canenter his home to give the medical assistance and that the potentiallydangerous domestic apparatus are switched off so that no danger to theuser's environment can be caused. It is also possible that in case themonitoring system is supplied together with an Automatic ExternalDefibrillator (AED) the station actuates a telephone module of the AEDin order to instruct a family member of the user how to operate thedevice in case the user is suffering from an cardiac arrest.

A still further embodiment of the invention is characterized in that thestation is a mobile station arranged to forward the alarm signal to aremote service center and in that said system further comprisespositioning means actuated by the alarm means, said positioning meansbeing arranged to determine a location of the user and to transmit asignal representative to said location to said remote service center.According to this technical feature the user is ensured of an adequatehandling of the problem also in case he is outside his home. In thiscase after a characteristic feature to a certain abnormality has beenderived from the acquired signal and the corresponding alarm signal hasbeen transmitted to the mobile station provided together with thesystem, the mobile station forwards the alarm together with aninformation about the location of the user to the remote service center.The information about the location of the user is collected by thepositioning means arranged in the system. An example of the positioningmeans is an interface to a Global Positioning System (GPS) which canprovide the co-ordinates of the user. These co-ordinates will then betransmitted together with the alarm signal to the remote service center.The service center will then forward the alarm signal together with theco-ordinates of the user location to the medical sites responsible for aproper handling of emergencies. Alternatively, for locations insidebuildings where no GPS signal can be acquired the positioning means canbe arranged to link up to a stationary in-door locating system. Anexample of such a locating system is known from U.S. Pat. No. 6,292,687.The known system is arranged to comprise a network of positionlocalizers, for example installed in every hotel room, each positionlocalizer emitting a characteristic beacon signal identifying thelocation. In case the positioning means are linked-up to such an in-doorlocating system the position of the user in-door can be registeredaccurately and transmitted to a service station together with the alarmsignal in case of an emergency.

A still further embodiment of the system according to the invention ischaracterized in that the user-side of the system further comprisesrange detection means arranged to validate that the user is locatedwithin an operational range of the station. This technical measure hasan advantage that the user-side of the system is enabled to checkwhether the user is still located within the operational range of thestation. This is of particular importance in case a mobile station isnot attached to the user-side of the system. Due to this technicalmeasure it is prevented that the user leaves home without the mobilestation on him.

A still further embodiment of the system according to the invention ischaracterized in that the monitor means further comprise a motion sensorarranged to monitor a physical activity of the user. This technicalfeature has the advantage that in case the monitoring system detects acardiac arrest this condition is double-checked by means of a motiondetector. Also, the motion detector can be arranged to prevent themonitoring system from gathering false data in case of a too extensivebody movement.

A still further embodiment of the system according to the invention ischaracterized in that the monitoring means are integrated in a wearablegarment. By integrating the sensors in a clothing, for example anelastic belt of an underwear slip or a brassier a patient-friendlymonitoring system can be obtained for continuous monitoring purposes. Bymeans of the elastic belt the sensors are constantly put under thenecessary pressure to ensure a constant position of the sensors withrespect to the user's skin. In case the wiring is integrated in thefabric of the elastic belt as well, a monitoring system can be obtainedproviding a maximum convenience and privacy to the user. An example of asuitable electrode material is a per se known electrically conductiverubber which has a certain degree of stretchability as well, adding tothe patient's comfort. By sealing off the electrical contacts betweenthe electrode material and the wiring a washable wearable monitoringsystem can be provided.

These and other aspects of the invention will be discussed withreference to the attached figures.

FIG. 1 a shows a schematic view of an embodiment of the systemarchitecture in case the user is located at his home.

FIG. 1b shows a schematic view of an embodiment of the systemarchitecture in case the user in located outside.

FIG. 2 shows schematically an embodiment of the components of theuser-side of the system according to the invention.

FIG. 3 shows schematically an embodiment of the electronics of thefront-end of the system of FIG. 2 in more detail.

FIG. 4 shows schematically an embodiment of the user-side of the systemintegrated into a wearable garment.

FIG. 5 shows schematically an embodiment of the components of the homestation module.

FIG. 6 shows schematically an embodiment of the components of the mobilestation module.

FIG. 7 shows schematically an embodiment of an operational flow-chart ofthe system according to the invention.

FIG. 1 a shows a schematic view of an embodiment of the systemarchitecture in case the user is located at his home. The user U isprovided with a detection and alarm system 10 comprising a user-side 1and a non-user side 2. The user-side 1 comprises monitoring means and afront-end electronics, both described in more detail with reference toFIGS. 2 and 3. The user-side 1 of the system is arranged to transmit analarm signal A, preferably via a RF-link to the non-user side 2 of thesystem 10. The non-user side 2 comprises a home station 2 arranged topick-up the alarm signal A and to forward the alarm signal to a remoteservice center 3 arranged to handle the medical emergency, for exampleby forwarding the alarm signal to a public emergency center 4.

FIG. 1b shows a schematic view of an embodiment of the systemarchitecture in case the user is located outdoors. The user U isprovided with a detection and alarm system 10 comprising a user-side 1and a non-user side 2′. The user-side 1 comprises monitoring means and afront-end electronics, both described in more detail with reference toFIGS. 2 and 3. The user-side 1 of the system 10 is arranged to transmitan alarm signal A, preferably via a RF-link to the non-user side 2′ ofthe system. The non-user side 2′ comprises a mobile station 2′ arrangedto pick-up the alarm signal A and to forward the alarm signal to aremote service center 3 together with an information about a location ofthe user U by means of a wireless connection. An example of a suitabletransmitting technology is GSM for the mobile station and the plain oldtelephone service (POTS) for the home station, etc. The remote servicecenter 3 is arranged to handle the medical emergency, for example byforwarding the alarm signal to a public emergency center 4.

FIG. 2 shows schematically an embodiment of the components of theuser-side 1 of the system according to the invention. The user-side 1comprises monitoring means 6 arranged to monitor a physiologicalcondition of the user. The monitoring means 6 comprise a set ofelectrodes 8 arranged on the body of the user to pick-up a signalcharacteristic of the physiological signal, for example an ECG signal, abody temperature, respiration rate, encephalogram, etc. Additionally,the monitor means 6 can comprise a sensor 8′ arranged to monitor asignal not directly related with a targeted physiological condition. Anexample of such a sensor is a motion sensor, or a blood pressure sensor.The monitoring means 6 are arranged to perform a continuous monitoringof a physiological condition of the user and are further arranged toprovide a corresponding signal to the front-end electronics 7 of theuser-side 1 of the system. The monitoring means 6 and the front-endelectronics 7 are worn on the body of the user, preferably at the waistarea. An example of the preferred embodiment of a body worn system isshown in FIG. 6. The front-end electronics 7 is arranged to analyze saidsignal in order to derive a feature characteristic to an abnormality inthe physiological condition of the user. For that purpose the front-endelectronics 7 comprise a preamplifier and analogue processing circuit11, an ADC unit 12, a L-processor 13, detection means 20, alarm means 15and transmission means 17. The detection means 20 comprise a sensorsignal interpretation unit 14 and feature extraction means 16. Theuser-side 1 of the system operates as follows: the monitoring means 6acquire the raw data which are delivered to the front-end 7. Thefront-end provides means for receiving the signals from the monitoringmeans, performs suited analogue processing by means of the analogueprocessing circuit 11. The processed raw data is converted into adigital format by means of the ADC 12 and is forwarded by a μ-processor13 to the detection means 20, where the condition of the user is beinganalyzed. For example, for cardiac applications the detection means 20can comprise a per-se known QRS-detector to determine R-R peak intervalsin heart cycles. The detection means 20 comprise a sensor signalinterpretation unit 14 arranged to derive a feature in the signalcharacteristic to an abnormal physiological condition of the user. Forexample, for cardiac or cranial applications said feature can be afrequency of the signal, for heamodynamic studies said feature can be athreshold value of a blood pressure and so on. It is also possible thatmore than one feature is assigned per monitored physiological condition.In this case the features can be ranked up according to the severity ofthe abnormality of the physiological condition being monitored. Forexample, for cardiac applications, a minor change in the cardiac cyclecan be recognized as an alarm of the lowest category, whereas anoccurrence of arrythmia or fibrillation can be ranked higher. The alarmsignal can be ranked accordingly to the rank of the feature. In bothsituations, the value of the feature or the features can be stored in alook-up table (not shown) of the memory unit 18. Additionally, thesystem can be arranged as a self-learning system, where the thresholdvalue for the feature is being adjusted and stored in the look-up tablein cases a pre-stored value does not correspond to an abnormal conditionfor a particular user.

In case the detection means 20 detects the abnormal condition, a signalis sent to the alarm means 15 to generate an alarm, which is transmittedby the transmitting means 17, for example by means of a RF-link. Thealarm signal is transmitted to the home station in case the userexperiences an abnormality at home, or, alternatively to a mobilestation for locations of the user away from home. From the respectivestation the emergency center is informed and is provided with the exactposition of the customer (at home/actual position outside home). Thealarm center takes over the management of the emergency and informs therespective communal or medical sites about the emergency, the location,patient data and the probable diagnose. This enables the fastestpossible treatment (early defibrillation) and gives an improved chanceto safe customers' lives.

FIG. 3 shows schematically an embodiment of the electronics of thefront-end of the system in more detail. The front-end electronics 7 iscomposed of an analogue input stage 72 which comprises circuits for alead off detection 71 to check the electrical contact with theelectrodes 8, an amplifier 73 and a low pass filter 75. The low passfilter 75 is preferably arranged with a 3 dB cut off frequency of 30 Hz.The signals at the output of the unit 72 are fed via a multiplexer unit85 to an ADC unit 81 of the μ-processor 80. The μ-processor 80 comprisesa software implemented to allow a sophisticated signal analysis, forexample a digital signal processing. For cardiac applications an exampleof the digital signal processing is a digital QRS detector and a digitaldetector for ventricular fibrillation. Additionally, the front-end 7comprises a band pass filter 76, preferably with a center frequency of16 Hz and a 3 dB bandwidth of 18 Hz. The signals from the band passfilter 76 are fed to an analogue signal detector 77. For cardiacapplications the signal detector 77 comprises a QRS detector that iscomposed of a full wave rectifier and a peak detector (both not shown inthe figure). The pulses from the signal detector 77 are fed to the input84 of the μ-processor 80 where the signals are further analyzed toderive a feature characteristic of the physiological condition of theuser. For cardiac applications such a feature can be an interval betweensubsequent characteristic peaks in the ECG spectrum, for example aninterval between subsequent R-peaks. The results of the signal analysiscan be stored in a memory block 105.

Additionally an interface 90 to a motion sensor 8′ can be integratedinto the front-end electronics 7. An example of a suitable sensor is aADXL202 from Analog Devices. Alternatively, the motion sensor can bepositioned directly at the electronics, a skin contact is not necessary.In that case the unit 90 is the motion sensor in FIG. 3. An on/offswitch 102 detects whether the user is wearing the electrodes 8 andperforms a shut down operation if the system is not used, for examplewhile the user-side of the system is being replaced. The powermanagement unit 110 is arranged to supply a stable voltage supply andcomprises standard low power devices.

The operation of the front-end electronics will be explained using anexample of the cardiac monitoring. The electrodes 8 supply a one-leadECG signal to the front-end 7 in a continuous mode. To allow ultra powerconsumption the ECG signals are only analyzed by the analogue QRSdetector 77. As long as the QRS pulses are within a defined limit,stored in an internal memory block 82 of the μ-processor 80, the systemassumes that the condition of the user is normal and no further actionis applied. This is referred to as an operational mode IDLE with aminimum power consumption. In case the QRS pulses fall outside thepre-stored limit or in case the signal quality degrades, the motionsensor interface 90 is actuated by the μ-processor 80. The interface 90detects whether there is a movement and the signal degradation or an(increased) heart rate is due to movement artifacts or due to anextensive exercise. In case the signal quality degrades substantiallythe lead-off detector 71 is actuated to check whether the electrodes arestill placed and connected to the user's body. In case the motiondetector gives no positive or unique result, and the lead-off detector71 validates that the electrodes are on the user's body, the ECG signalis sampled, preferably with 100 samples per second by the ADC unit 81 ofthe μ-processor 80 and is supplied to the digital detector 83 forspecial digital processing. This operation is referred to as an ALERTmode. In case the processing detects an emergency according to thederived feature an alarm signal is sent to the home or mobile stationvia a RF-link 120. This mode of operation is referred to as an EMERGENCYmode. The above operational modes of the front-end will be discussed inmore detail with reference to FIG. 8. The respective station is arrangedto provide a local alarm and to forward the alarm signal to a remoteservice center responsible for an adequate medical response to anemergency.

FIG. 4 shows schematically an embodiment of the user-side 1 (see FIG.4a) of the system integrated into a wearable garment, preferably into anelastic belt of an underwear slip or a brassier. The components of theuser-side according to the present embodiment of the system are attachedto the elastic belt 60 that can be locked with a help of an elastic band62. A set of electrodes 64 is provided to monitor a signalcharacteristic to a targeted physiological condition of the user. Forcardiac applications, for example the set of electrodes 64 can bearranged to measure an ECG signal. In this case it is sufficient to usethree electrodes that obtain a one-lead ECG measurement. The electrodescan be of a dry type and can be glued or attached differently on thebelt 60. Wires (not shown) can be provided in different ways, forexample the wiring can be integrated into the fabric of the elastic beltor an external wiring can be used. Wires establish electricalconnections to the front-end electronics 70 as well as provideelectrical connections from a battery 66 to the front-end electronics 70for the power supply. The front-end module 70 can comprise the unitsdiscussed with reference to FIG. 3. In order to satisfy to therequirements of a wearing comfort, the battery 66 can be manufactured asa flexible battery, for example a lithium ion battery and the front-endelectronics 70 can be carried by a flexible foil (shown in FIG. 4b). Itis also possible to divide the front-end electronics 70 into a number ofunits, preferably two units, each unit separately carried by theflexible foil for a better weight distribution of the units across thebelt 60.

FIG. 5 shows schematically an embodiment of the components of the homestation module 30. The home station module 30 is arranged to work in acontinuous mode 24-hours a day and operates in a full-automatic modewithout user interaction. The position of the home station is known,which is the user's address. Therefore, a localization of the user incase of an abnormality is not necessary. The home station 30 is activeif the customer stays at home and is actuated by means of an RF-link 32which is controllable by the user-side of the system (not shown in thefigure). The RF link 32 is the counterpart of the front-end RF link andcan be an off-the-shelf 868 MHz RF module using e.g. FM modulation toconnect to the front-end. The operation for the home station 30 iscontrolled by a μ-processor 36. The home station 30 comprises means 34to generate a local alarm in case the abnormality is detected. Further,the home station 30 comprises means 33 to forward the alarm signal to aremote service center (not shown) together with an information about theuser's address provided by the unit 35. The unit 39 is arranged toactuate a telephone link to the remote service center for furtherhandling of the alarm. The link 39 to the alarm center can be a standardtelephone modem. There is a possibility for the user to overrule thegenerated alarm by means of the user interface 37, which is necessary incase a false alarm is generated. The home station 30 further comprises arange detection means 38 arranged to verify whether the user is withinthe range of the RF-link 32.

It is also possible to use the range detection unit 38 to warn the userthat he is outside the range. The RF link of the front-end of theuser-side of the system (not shown in the figure) can be arranged tosend a short message with an identifier and to listen afterwards for areply from the RF-link 32 of the home station 30. In case the reply hasbeen received the front-end will return to a stand-by mode, otherwise aspecial beeper on the front-end will generate a warning. The rangingfunction can be started at fixed time intervals, for example everyminute, or with a variable time intervals, for every 5 minutes or can becontrolled by the motion detector allowing for longer periods during arest of the user. According to this technical measure a sophisticatedand reliable monitoring and alarm system can be produced. Theoperational configuration of the home station 30 is controlled by aμ-controller (not shown) which is responsible for configuration of alarmmessages, controlling the modem and the RF transceiver, self-testing andout-of-range detection, when applicable. Local alarm functionality canbe provided by acoustic and visible alarming means (e.g. beeper, loudspeaker) in a range up to 50 m to inform nearby people about the cardiacemergency situation. Indicator e.g. LEDs can be provided to show theactual status of the system. Optionally, a LCD display can be providedto show status messages and display vital parameters such as heart rate.

FIG. 6 shows schematically an embodiment of the components of the mobilestation module. The mobile station 40 is actuated in case the user staysoutside his home and has the same functionality as the home station. Themobile station comprises an RF-link 42, a local alarm means 44, aμ-processor 46, emergency call configuration means 43, user interface47, wireless link 49 to a remote service center. The mobile station canalso be equipped with an out of range detection means 48 which operateaccording to the same principle as a similar unit of the home station ofFIG. 5. Due to the fact that the user is located outside his home, hisexact dwell position must be known in case an emergency occurs.Therefore the mobile station 40 comprises positioning means 45 arrangedto determine the actual position of the user on-line. An example of thepositioning means is an interface to a Global Positioning System (GPS)which can provide the co-ordinates of the user. These co-ordinates willthen be transmitted together with the alarm signal to the remote servicecenter. The service center will then forward the alarm signal togetherwith the co-ordinates of the user location to the medical sitesresponsible for a proper handling of emergencies. Alternatively, forlocations inside buildings where no GPS signal can be acquired thepositioning means can be arranged to link up to a stationary in-doorlocating system. The mobile station 40 can be implemented to comprisetwo parts: a standard handy (guaranteed communication coverage) with anintegrated modem and a localization part (e.g. a GPS receiver and microcontroller for determination of the actual position). The localizationpart can be integrated in a handy clip or a cellular phone pocket. Themobile station operates in a full-automatic mode without userinteraction if the user stays outside home. The position of the mobilestation is not known, therefore the localization of the customer has tobe determined on a regular base this can be performed by means of theGPS system.

FIG. 7 shows schematically an embodiment of an operational flow-chart ofthe system according to the invention. To minimize the power consumptionthe system operates in different modes. After a boot operation,schematically presented by a block 92 the system performs a self-testprocedure 94. Examples of check procedures are a power check, electrodeon/off check, links check, periphery check, etc. In case the checkprocedure is passed the system switches to the IDLE mode 96, otherwisethe system enters an error state 97. In the latter case a warningmessage can be sent by means of an audible or a visual signal by meansas shown by step 99. The IDLE mode 96 is a standard mode of the systemcharacterized by a minimum power consumption. Preferably, only in theIDLE mode user interactions 103 and service interactions 98 can beexecuted. The system remains in the IDLE mode in case the signal fromthe monitoring means shows no abnormalities. In case the user decides toswitch off the system, this action is detected at a switch-off step 95,leading the system to a shut-down mode (not shown). In case anabnormality is detected during the monitoring, the system changes to anALERT mode 101, where an extended monitoring takes place. In case anabnormality is not caused by a deterioration of the physiologicalcondition of the user, the system return to the IDLE mode 96. Otherwise,the system enters an EMERGENCY mode 104 where an alarm signal isgenerated and communicated to external devices, such as the home stationor the mobile station. Therefore, the system architecture is developedto ensure that the system has a low power consumption during a normaloperational state leading to an increased durability of the system. Thisfeature is of a particular importance for ensuring reliable monitoringin a continuous mode during extended periods of time.

1. A system for detecting an abnormality in a physiological condition ofa user and for alerting people to said abnormality, said systemcomprising monitor means for monitoring a signal representative of thephysiological condition, said monitor means comprising: sensor meansarranged to be located on the body of the user for detecting saidsignal; detection means actuated by said sensor means and arranged toprocess said signal in order to derive a feature in the signalcharacteristic to said abnormality; alarm means arranged to trigger analarm signal upon a detection of said feature by the detection means;and transmission means arranged to transmit the alarm signal to astation responsive to said alarm signal, characterized in that thedetection means are arranged on a user-side of the system, the alarmsignal being the sole signal transmitted by the monitor means to saidstation.
 2. A system according to claim 1, characterized in that thestation is a stationary home-based station arranged to forward the alarmsignal to a remote service center.
 3. A system according to claim 2,characterized in that said home-based station is further arranged tocontrol a domestic device.
 4. A system according to claim 1,characterized in that the station is a mobile station arranged toforward the alarm signal to a remote service center and in that saidsystem further comprises positioning means actuated by the alarm means,said positioning means being arranged to determine a location of theuser and to transmit a signal representative to said location to saidremote service center.
 5. A system according to claim 1, characterizedin that the user-side of the system further comprises range detectionmeans arranged to validate that the user is located within anoperational range of the station.
 6. A system according to claim 1,characterized in that said abnormality in the physiological condition isa condition of the cardiac arrest.
 7. A system according to claim 5,characterized in that the system further comprises an automatic externaldefibrillator device provided with a telephone module actuatable by theremote service center in case of an emergency.
 8. A system according toclaim 1 characterized in that the monitor means further comprise amotion sensor arranged to monitor a physical activity of the user.
 9. Asystem according to claim 8, characterized in that the monitoring meansare integrated in a wearable garment.